Fares are complicated, but cheap.
Torremolinos has a 10-journey ticket but I think it's only valid on the local routes. In Málaga, EMT has a similar card product on their excellent network with changes within the hour included, and you really can pay with contactless bank cards on many (most? all?) buses - those with the usual logo. There is a separate validator for them.
If travelling more widely or between the areas the transport authority (Consorcio de Transporte) has
their own card that can be used for PAYG on all modes but contains an extra complication - it is configured for the number of zones you need at purchase or whenever more money is added. In practice that might not matter as the fares are so cheap, so you can overpay. There is a small charge when changing vehicles (except between Málaga urban buses). The card can be used in other Andalusian regions where it follows whatever impenetrable fare structure they have.
On trains, IIRC these cards (unbelievably) are used to buy a ticket from a machine, which might end up on Renfe's own contactless ticket

. Contactless bank cards can be used on the local trains C1 and C2.